The present invention relates generally to a rotary piston, internal combustion engine and, in particular, to a circular piston engine of the trochoid type, having a piston arranged to rotate planetary-fashion within a surrounding housing. The piston has inlet and outlet channels or passages arranged therein for the inflow and outflow, respectively, of the working medium. The inlet and outlet channels lead to inlet and outlet openings arranged on the periphery of every other arcuate lobe of the piston, such inlet and outlet openings being controlled by the disposition of the particular lobe of the piston in relation to the working chambers formed by arcuate recesses in the housing.
In known rotary piston, internal combustion engines of the above-described type, no special valve members or devices are employed to control the charge alternation (inflow and outflow of gases) within the engine. Rather, the exchange of gases has been allowed to take place as the inlet and outlet openings, arranged on the periphery of the piston, move into and out of the several arcuate working chambers arranged in the housing. In order to carry out a four-cycle process in such an internal combustion engine, the inlet and outlet openings are arranged on every other lobe of the piston, the inlet opening being arranged in the posterior region of the lobe, in relation to direction of rotation of the piston, and the outlet opening in the anterior region thereof.
Now it has been found that in the regions of the top dead centers of each piston lobe having the inlet and outlet channels an overlap of inlet and outlet channels occurs in each of the several working chambers. This overlap begins at the moment when an inlet opening enters a working chamber and ends when the outlet opening situated on the same lobe of the piston exits from that working chamber. This inlet and outlet channel overlap permits gases to flow through both the inlet and outlet opening at the same time, resulting in gas exchange losses. These gas exchange losses occurring during this overlap impair the efficiency of the engine.